Evaluation of imaging techniques for early detection of intrathoracic cancers in symptomatic patients in primary care: a systematic review

Our plain-English summary of Evaluation of imaging techniques for early detection of intrathoracic cancers in symptomatic patients in primary care: a systematic review, by B. Grigore, J.L. Peters, W. Hamad, et al (BMJ Open, 2025).

The study

• Authors: B. Grigore, J.L. Peters, W. Hamad, N. Calanzani, L. Asare, F.M. Walter, R. Neal
• Journal: BMJ Open
• Published: 2025;15(8):e091435
• Type of article: Systematic review
• Read it: PubMed · Publisher · Free full text

Abstract

Objectives: Intrathoracic cancers, such as lung cancer, mesothelioma and thymoma, represent diagnostic challenges in primary care. We aimed to summarise evidence on the performance of imaging techniques that could aid the detection of intrathoracic cancers in low prevalence settings.

Design: Systematic review and quality appraisal using Quality Assessment of Diagnostic Accuracy Studies-2 and Grading of Recommendations Assessment, Development and Evaluation.

Data Sources: MEDLINE, Embase and Web of Science were searched with a predesigned search strategy for articles from January 2000 to January 2024.

Eligibility Criteria: We included studies relevant for primary care, where participants were suspected of having intrathoracic cancer and reported on at least one diagnostic performance measure. We excluded studies where the cancer diagnosis was already established. Data extraction and synthesis screening were conducted independently by two reviewers. Data extraction and quality appraisal were conducted by one reviewer and checked by a second reviewer.

Results: Out of 30 539 records identified by the database searches, 13 studies were included. There was heterogeneity in the types of cancers, populations included and reported diagnosis pathways for suspected cancers. Imaging modalities investigated included chest X-ray (three studies), computer tomography (CT, six studies), magnetic resonance imaging (two studies), positron emission tomography CT (two studies), ultrasound (two studies) and scintigraphy (one study). Chest X-ray sensitivity reported for lung cancer ranged from 33.3% to 75.9%, with specificity ranging from 83.2% to 95.5%. For CT, reported sensitivity varied from 58% for pleural malignancy to 100% for lung cancer. One study investigating an artificial intelligence tool to detect lung cancer found poor detection performance in a real-world patient cohort.

Conclusions: We found a limited number of studies reporting on the diagnostic performance of usual imaging techniques when used in unselected primary care settings for the diagnosis of intrathoracic cancer in symptomatic patients. There is a need for more studies evaluating such techniques in the general population presenting in primary care, where the prevalence is relatively low. A better understanding of the performance could lead to better detection strategies for intrathoracic cancers in primary care. Intrathoracic cancers, such as lung cancer, mesothelioma and thymoma, represent diagnostic challenges in primary care. We aimed to summarise evidence on the performance of imaging techniques that could aid the detection of intrathoracic cancers in low prevalence settings.

© Author(s) (or their employer(s)) 2025. Re-use permitted under CC BY. Published by BMJ Group.

In plain English

This was a systematic review of studies published from January 2000 to January 2024. It asked how well imaging tests detect intrathoracic cancers, including lung cancer, mesothelioma and thymoma, in adults suspected of cancer in settings relevant to primary care. Thirteen included studies covered chest X-ray, CT, MRI, PET-CT, ultrasound and scintigraphy.

Chest X-ray sensitivity for lung cancer ranged from 33.3% to 75.9%. CT sensitivity ranged from 58% for pleural malignancy to 100% for lung cancer. The 100% figure came from CT combined with sputum cytology in asymptomatic asbestos-exposed people. In the 58% study, only 59 of the 195 cases detected were primary mesothelioma.

Another study screened 972 asbestos-exposed people. At a 2 mm nodule threshold, X-ray had a sensitivity of 33% and a specificity of 95%, and CT had 83% and 78%. An artificial intelligence tool applied to X-rays requested by general practitioners performed poorly.

The authors concluded that there was limited information on these tests in unselected primary care patients and that more studies are needed. They noted that most included studies were small and enrolled patients with a high suspicion of cancer.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Systematic review of diagnostic accuracy studies, with risk-of-bias appraisal (QUADAS-2) and evidence grading (GRADE); no meta-analysis
• Who was studied: 13 included studies of adults suspected of intrathoracic cancer: five in the UK, four in China, two in Germany, one in France and one in Italy. Most studied symptomatic patients. Two studied asymptomatic, high-risk asbestos-exposed people, and one studied patients with non-specific respiratory symptoms.
• Exposure: Imaging tests: chest X-ray (three studies), CT (six), MRI (two), PET-CT (two), ultrasound (two) and scintigraphy (one), including one artificial intelligence tool for chest X-ray. Two included studies concerned asbestos-exposed workers.
• Main results:
  • Across included studies, chest X-ray sensitivity for lung cancer ranged from 33.3% to 75.9%, and specificity ranged from 83.2% to 95.5%.
  • Across included studies, CT sensitivity ranged from 58% for pleural malignancy to 100% for lung cancer.
  • The 100% CT figure came from the study of asymptomatic asbestos-exposed patients (Felten et al.), where CT was used in combination with sputum cytology, not alone.
  • In patients who underwent contrast-enhanced CT for suspected pleural malignancy (Tsim et al., 315 patients), specificity was 80%. Only 59 of the 195 cases detected were primary mesothelioma; the rest were secondary malignancies.
  • In 40 patients with suspected malignant pleural effusion (Traill et al.), contrast-enhanced CT had a sensitivity of 84.4% and a specificity of 62.5%.
  • In an asbestos-exposed screening population (Clin et al., 972 patients, 1230 investigations), bronchopulmonary cancer was detected at a rate of 0.82% by chest X-ray and 2.16% by chest CT.
  • In the same asbestos-exposed population, at a 2 mm nodule threshold, chest X-ray had a sensitivity of 33% and a specificity of 95%, and CT had a sensitivity of 83% and a specificity of 78%.
  • An artificial intelligence tool applied to 5722 chest X-rays requested by general practitioners underperformed compared with a multidisciplinary team, with a positive predictive value of 5.6% (95% CI 4.8% to 6.6%).
  • Only five studies (Bhartia, Bradley, Maiter, Tsim and Yang) were judged high quality of evidence under GRADE.
• The authors' conclusion: The authors concluded that there was limited information on how usual imaging techniques perform for diagnosing intrathoracic cancer in symptomatic patients in unselected primary care. They said more studies, particularly of CT, are needed in the general population presenting in primary care.
• Limitations the authors state:
  • Most included studies enrolled patients with a high suspicion of cancer, so the results may not generalise to primary care.
  • Many included studies had small samples; only half had more than 100 participants.
  • Heterogeneity between studies prevented a meta-analysis.
  • Because the search was narrowed to a manageable size, relevant studies may have been missed.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer, Mesothelioma.

Medical terms in this study, explained in our Lexicon: Intrathoracic, Systematic Review, Lung Cancer, Mesothelioma, Chest X-Ray, Ultrasound.

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